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A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyrights.
1. Field of the Invention
The present invention relates generally to helicopter external load operations, and more particularly, to a method for transferring loads from an airborne helicopter to a structure or elevated component thereof, while simultaneously providing fall protection for the load and emergency release capabilities for the helicopter during the entire transfer.
2. Description of the Background Art
Rotary winged aircraft, such as helicopters, have been used in a wide variety of load transfer operations. Human external load operations (HEL) typically involve the transportation of a passenger suspended by a cable assembly under the helicopter. For example, helicopters equipped with load suspension points, or hooks, are capable of transporting loads in sling configuration wherein the load is suspended beneath the helicopter by a suspension apparatus. In other applications, helicopters carry cargo as well as human loads in various configurations external to the fuselage, such as on the skids or on skid-mounted platforms. For example, load-bearing platforms may be affixed to the helicopter to permit persons to operate external to the crew compartment. In other situations, a person may stand on one of the helicopter landing skids and operate in the external environment. HEL operations are commonly performed in transmission line maintenance and repair procedures in the electrical power industry, in the logging industry to access remote work sites, and for emergency rescue operations.
There are a number of basic devices, such as safety harnesses, for use in HEL operations. While the design of known safety devices varies, harnesses commonly consist of shoulder straps attached to a waist or chest belt. Some harnesses incorporate suspender style straps with a tether point-of-attachment on the front center of the chest/waist strap. Others comprise a Y-shaped design, where the shoulder straps aare connected to a strap extending vertically from the waist belt to form a three-point intersection. These harnesses are typically constructed of nylon webbing, and commonly include padding. The harness is designed to support the load (i.e., body weight) by the torso and shoulders of the user for suspension from a helicopter. Sit harnesses comprise another category of HEL devices. Also known as pelvic harnesses, bosun""s seat, rescue harnesses or rigger""s harnesses, these devices suspend the user in a seated posture. The basic design of a sit harness includes a waist belt connected to leg loops routed around the top of the thighs. The point of the tether attachment typically extends directly in front of the upper pelvic region. Full-body harnesses (FBHs) comprise a combination of sit harnesses and chest harnesses. While there are a number of variations of the basic design of the harness, all full-body harnesses include leg loops, shoulder straps, and either a waist belt, a chest belt, or both. The design of the full body harness is such that it assists the user in maintaining an upright, seated posture while suspended from the helicopter.
The present inventor has contributed significantly to advances in helicopter external load operations, particularly external human load operations. My U.S. Pat. No. 4,673,059 discloses a method and system for placing a load, which may consist of a combination of personnel and equipment, on or in proximity to components of an energized power transmission line. My U.S. Pat. No. 5,417,304 discloses a method for suspending a load from a rotary winged aircraft, such as a helicopter, using an apparatus that incorporates an emergency release activated by the suspended person. The methods disclosed in the ""059 and ""304 patents concern loads suspended beneath a helicopter, and do not provide for adequate fall protection for the external load.
In certain situations, however, it is necessary or desirable to transfer external loads from a hovering helicopter to a structure, such as a power transmission tower or an energized or de-energized power transmission line, ground wire, or other elevated point or structure. The methods disclosed in the ""059 and ""034 patents do not disclose suitable apparatus or methods for accomplishing the transfer of an external load from a hovering helicopter to an elevated structure while maintaining adequate safeguards for both the helicopter as well as the load. While the ""304 patent discloses an emergency release, the system disclosed therein is a release-on-command type system that requires the suspended person to: (1) realize the existence of an emergency with the helicopter; and (2) manually activate the quick release to permit the helicopter to pull away. As should be apparent, the primary concerns in such human transfer applications involve maintaining adequate fall protection for the person during the transfer procedure without limiting helicopter operations, particularly the availability of emergency maneuvers and operations. It is critical to maintain full fall protection for the person through the entire transfer process, while, at the same not limiting the operation of the helicopter in emergency situations.
Currently, there is little standardization and a general lack of safety procedures practiced by those performing HEL operations. While regulations exist regarding the physical and structural characteristics of external load operations, little consideration has been given to the issue of humans as external loads. Federal Aviation Regulations applicable to rotorcraft operations, particularly those referring to human external loads, are found in Title 14 of the Code of Federal Regulations (CFR). The collection of FAA regulations found in 14 CFR is often referred to as the Federal Aviation Regulations (FARs). Within 14 CFR, part 133 pertains directly to rotorcraft external load operations and contains subparts that address applicability, certification rules, operating rules, and related requirements. In addition, part 27 requires that any external load attaching means must include a quick-release system to enable the pilot to release the external load quickly during flight. While the regulations address a number of areas, they provide no specific detail regarding the attachment method, human load transfer methods, or the structure or function of quick-release devices.
As a result of the lack of adequate safety methods there have been a number of rotorcraft accidents in connection with HEL operations. During the period from 1973 through 1995, it has been reported that there were 473 external load operations in which the helicopters were involved in either an accident or an incident. Of the 473 accidents listed, a substantial number involved operations using a sling line or sling load. Accordingly, it is recognized that the predominant cause of external load accidents involves problems with the sling line/load.
One common, yet inherently risky prior art method of transferring an external human load from a hovering helicopter to a structure, in a non-sling configuration, consists of bringing the helicopter to a hover immediately adjacent to a structure, wherein the helicopter may be stabilized by the placement of one or both skids (or wheels) on the structure, thereby allowing the person to step from the helicopter to the structure. This method, however, is significantly flawed in that, to avoid tethering the helicopter to the structure and thereby limiting the availability of emergency flight procedures (e.g. emergency pull-away), there exist periods of time during the transfer that the person is without fall protection, and consequently at substantial risk.
Thus, although HEL operations have been practiced, there remains a need for safer methods for transferring external loads from hovering helicopters. More particularly there exists a need for an improved method of safely transferring a load from a hovering helicopter to a structure, such as a power transmission tower or line or any other elevated structure, while simultaneously providing total fall protection for the human and preserving emergency operating procedures for the helicopter and crew by incorporating an emergency quick release.
The present invention addresses the shortcomings of the background art by providing a method for transferring loads from an airborne rotorcraft while providing fall protection and emergency release capabilities for the aircraft. According to a preferred embodiment, a helicopter is adapted with an external platform configured for carrying a load external to the aircraft fuselage which load is restrained by an FAA approved safety restraint (e.g. seat belt). The load is equipped with a safety harness and a lanyard apparatus having first and second lanyards connected to the harness. The method is primarily directed to transfer of the load from the hovering aircraft to an adjacent structure. According to the method, a helicopter hovers next to a structure, and safe transfer is accomplished by: (1) connecting a safety lanyard apparatus, having first and second lanyards, to the load; (2) securing the load to the helicopter with a safety restraint (e.g. FAA approved restraint, seatbelt, or one of said lanyards) (3) attaching the free end of the first lanyard to the helicopter; (4) releasing any auxiliary safety restraint; (5) attaching the free end of the second lanyard to the structure; (6) detaching the first lanyard from the helicopter; and (7) transferring the load onto the structure. When transferring from the structure to the helicopter the method is essentially reversed, however, the first lanyard is always used for connection to the helicopter and the second lanyard is always used for connection to the structure. When transferring loads as described, fall protection is provided since the load is safely tethered to a load bearing structure at all times. In addition, the lanyard apparatus includes a quick release mechanism to simultaneously provide an emergency release that allows the aircraft to instantly pull away without placing the external load at risk.
Fall protection and emergency release capabilities are provided by an emergency release lanyard apparatus. The lanyard apparatus provides total fall protection for the load throughout the transfer process without restricting or otherwise limiting available emergency flight options/maneuvers by incorporating an emergency release that automatically activates on demand. In a preferred embodiment, the emergency release lanyard apparatus includes first and second load bearing lanyards, each terminating in a free end incorporating a hook. The competing concerns of fall protection (for the load) and on-demand emergency release (for the aircraft) are each enabled by providing the first lanyard with a quick release mechanism and the second lanyard with a limited slip mechanism.
Each lanyard is attached to a common point, such as a load bearing steel O-ring, which in turn is attached to a safety harness which secures the load. Each lanyard has a free end incorporating a double-action locking hook attached thereto. The first lanyard incorporates a quick-release mechanism, which, upon activation, results in the separation of the hook and free end portion thereof. The second lanyard incorporates a limited slip mechanism, which, upon application of a predetermined force thereon, activates the first lanyard""s quick-release mechanism. The use of the emergency release lanyard apparatus according to the methods disclosed herein provides total fall protection during the transfer of a load from a hovering rotorcraft to a structure while providing an on-demand quick-release in emergency situations.
Accordingly, it is a primary object of the instant invention to provide improvements in the field of helicopter external load operations.
Another object of the present invention is to provide a system, including apparatus and methods, for providing comprehensive fall protection for a person or thing during transfer from a hovering rotorcraft to an elevated structure.
Still another object of the present invention is to provide a system that provides fall protection for a human external load engaged in an airborne transfer, before, during, and after transfer to a structure.
Yet another object of the present invention is to provide a system for HEL operations that provides an emergency release for a helicopter tethered to a structure while transferring human and non-human loads to or from the structure.
Still another object of the present invention is to provide a system for HEL operations that permits for release of a helicopter tethered to a structure while transferring a load to or from the structure, without the requirement for human action.
Another object of the present invention is to provide an apparatus for use in transferring loads from a hovering rotorcraft to a structure while providing total fall protection and incorporating an emergency release that does not require activation by the person being transferred.
In accordance with these and other objects, which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings.